body{
    font-family: 'PingFangSC-Regular', 'helvetica neue', tahoma, 'PingFang SC', 'microsoft yahei', arial, 'hiragino sans gb', sans-serif;
    /*background: #000;*/
}
.test{
    line-height: 30px;
    background: #0f0;
    text-align: center;
}
#backBtn{
    line-height: 30px;
    /*background: #0054e1;*/
    background: #ddd;
    text-align: center;
}
/*---------------头部开始---------------*/
header{
    /*height: 74px;*/
    /*background: red;*/
    /*position: relative;*/
    /*z-index: 999;*/
}
.top_iframe{
    /*height: 500px;*/
    /*width: 100%;*/
    /*border: none;*/
}
.nav-box{
    height: 74px;
    /*position: fixed;*/
    position: absolute;
    z-index: 10;
    top: 0;
    /*background: rgba(0,0,0,0);*/
}
.logo{
    line-height: 4rem;
    font-size: 1.5rem;
    letter-spacing: 0.1rem;
}
.nav-center{
    height: 74px;
}
.nav-center .js-nav-link{
    color: #fff;
}
.nav-center:hover .js-nav-link{
    color: #000;
}
.js-nav-language{
    color: #999;
    text-decoration: none!important;
}
.js-nav-language:hover{
    color: #7e7e7e;
}
.nav-center a{
    padding: 0;
    font-weight: bold;
    box-sizing: border-box;
    text-decoration: none;
}
.nav-center li{
    width: 120px;
    line-height: 74px;
    text-align: center;
    box-sizing: border-box;
}
.nav-center .summary{
    height: 0;
    overflow: hidden;
    transition: all 0.4s linear 0s;
}
.nav-center .js-nav-item:hover .summary{
    display: block;
}
.nav-center .summary li{
    line-height: 40px;
}
.nav-center .summary li a{
    text-decoration: none;
    font-weight: lighter;
    color: #737373 !important;
}
.nav-center .summary li a:hover{
    color: #000!important;
}
.navbar-bg .nav-bg{
    width: 100%;
    height: 0;
    background: #fff;
    position: absolute;
    top: 0;
    z-index: -1;
    transition: all 0.4s linear 0s;
    overflow: hidden;
}
/*---------------头部结束---------------*/

@media (min-width: 1px){
    .nav-center li{
        line-height: 40px;
    }
    .nav-center .summary{
        display: none!important;
    }
}
@media(min-width: 576px){

}
@media (min-width: 768px) {
    .nav-center li {
        width: 70px;
        line-height: 74px;
    }
    .navbar-expand-md .navbar-nav .js-nav-link {
        padding-right: 0.1rem;
        padding-left: 0.1rem;
    }
    .nav-center .summary{
        display: block!important;
    }
}
@media (min-width: 992px) {
    .nav-center li{
        width: 90px;
    }
}
@media (min-width: 1200px) {
    .nav-center li{
        width: 120px;
    }
}